Polarized relay



April 29, 1958 H. P. LUHN POLARIZED RELAY Filed June 1; 1954 4Sheets-Sheet 1 HANS P. LU HN BY f [3W 8M, MZPW ATTORNEYS April 29, 1958H P, LUQN 2,832,867

POLARIZED RELAY Filed June 1, 1954 4 Sheets-Sheet 2 FIG. 2

FIG. 3 4|0 4 47 45 SSH/4T0 as I 32 320 l 48 1 38 [I j I {I 50 I I 28 28a49 i i I5 I I 150 5&3

INVENTOR. HANS P. Lu HN ATTORNEYS April 29, 1958 H. P. LUHN 2,832,867

POLARIZED RELAY Filed June 1, 1954 4 Sheets-Sheet 3 I FIG. 5

ATTORNEYS April 29, 1958 H. P; LUHN POLARIZED RELAY 4 Sheets-Sheet 4Filed June 1. 1954 JNVENTOR. HANS P LUHN ATTORNEYS ilnited. StatesPatent POLARIZED RELAY Hans P. Luhn, Armonk, N. Y., assignor toInternational lllnsiness Machines Corporation, New "York, N, EL, acorporation of New York Application June 1, 1954, Serial No. 433,552

7 Claims. (Cl. 200-93) This invention relates to polarized relays of thetype wherein permanent magnets are employed to hold the relay in eitherof its operating positions after the circuit is broken through the coilof the relay whose action opens and closes the contacts. Such relays arewidely used in many and various instruments and apparatus whereinelectric circuits must be rapidly and repeatedly opened and closed andpositively held in position, notwithstanding the mechanical vibration,electrical disturbances and the like which are unavoidable in varioustypes of apparatus in which such relays are employed.

One of the most important requisites of a relay of this character isspeed of operation, for in many forms of apparatus such, for example, aselectronic accounting machines the speed of operation of the relays is alimiting factor in the overall speed of operation of the machine.

The object of my invention is to provide a relay of this character whichwill operate at a high rate of operations per minute, will make a goodelectrical contact and will be maintained in its open or closed positionnotwithstanding the substantial mechanical vibration and electricaldisturbances incidental to the operation of an electronic accountingmachine.

A further object of the invention is to provide a relay of thischaracter which is not subject to significant wear even over longperiods of operation.

A further object of the invention is to provide a relay of thischaracter which may be readily assembled in multiple units in a commonframe or casing, and may be housed in a small space, and utilized invarious circuits without disturbing the relays themselves or theirmountings.

In the accompanying drawings I have disclosed a preferred embodiment ofmy improved relay in the form in which it is now made for commercialuse. I have selected for illustration a unit containing eight two-wayrelays.

In the said drawings,

Fig. l is a vertical section of the unit taken on line 1l-l of Fig. andshowing a relay and its supporting panel in front elevation and drawn toa greatly enlarged scale;

Pig. 2 is a vertical transverse section taken on line 2-2 of Pig, 1 anddrawn to the same scale;

Fig. 3 is a similar section taken on line 3-3 of Fig. 1;

Fig. 4 is a plan view (drawn to a smaller scale) of the base of therelay unit but with the relays, panels and cover removed and the upperportion of the base broken away and shown in section;

Fig. 5 is a vertical section taken on line 5-5 of Fig. 4 and drawn tothe same scale, with the relays and their supporting panels in position;and

Figs. 6 and 7 are face views of a supporting panel showing the front andrear sides before the relays are attached.

Referring to the drawings, 1 indicates the base of the unit which is ofinsulating material, preferably molded phenolic resin plastic, havingformed therein a series of rectangular recesses 2 (Fig. 4) connected byslots 3 to receive the lower edge of the supporting panels 4 on whichthe relays 5 are mounted. The panels 4 are also made of plastic, andpressed into the surface of the panel on each side along the bottom edgeare a series of contact strips copper, strips SlS6 (Fig. 1) being on thefront of the panel, and strips S7-Sl2 on the rear (Fig. 7). These stripsmay be fused directly to the plastic when the panel is made, orotherwise attached, with their surfaces approximately flush with thesurfaces of the panel.

A panel may be placed in any of the four rows of six holes 2 and slots 3shown in Fig. 4. The panel is held in position by the frictionalengagement of spring contact members two of which are mounted in each ofthe holes 2, as shown in Figs. 4 and 5. These contact members havespring fingers Flt-F6 which engage the respective contact strips Sll-S6on the front side of the panel, and fingers 1 7-1 12 which engage thecontact strips S7Sll.2 on the opposite side of the panel. These springfingers serve both to hold the panel in upright position and also tomake electrical connections with the respective copper strips S1-S12.

Connections with the desired external circuits are made through thesespring fingers Fl--Fl2, and conventional type circuit plugs a may bereceived in recesses 7' in the bottom of base 1 and have theirconnecting portions in engagement with conventional receptacle tubes, 8associated with the respective contact members which support the fingersFl-Fl2.

Connections on each panel 4 may be made between. various parts of therelays 5 and the contact strips S1S6= on one side and 87-812 on theopposite side in any de--- sired manner, for example, by employingconventional insulated wires each soldered or otherwise connected at oneend to the respective contact strips, and at their oppo site ends to theappropriate part of the relay. Preferably, however, such connections aremade in part by means of conventional insulated wires, and in part bymeans of.

the metallic strips shown in Figs. 6 and 7 which are: formed asextensions of certain of the contact strips; Si-Si2, and which are fusedflush into the respective surfaces of panel 4.

Thus, referring to Fig. 6, contact S2 has a metallic extension 9 whichbranches to the opposite sides of the plate and terminates in twometallic contact mounts 10 and 11 for two of the fixed contacts (to bedescribed) of one of the relays These mounts are connected by means ofhollow rivets, used in assembling the relay structure, to be referred tolater, with contact mounts 10a. and 11a on the opposite side of thepanel (Fig. 7 A third contact mount 12 at the top front of the panelsupports a third fixed relay contact and is similarly connected to amount 312a on the opposite side of the panel, and this mount isconnected through an extension 13 with contact strip SS. Similarly,contact strips S3 and S6 have extensions which terminate in mounts l4and 15 for other parts of the relay. Also contact strips Sh and S12 haveextensions terminating in similar mounts 14a and 15a.

There are three coils on each side of each panel, the three coilstogether forming two independently operated two-way relays both of whichmay be actuated to one of their two positions at the same time, or oneto one position and the other to the opposite position, so that eachpanel provides four separate relays. In the arrangement shown there aretwo separate panels (Fig. 5) making a total of twelve relays enclosed bya cover 18, the lower edge of which is received on base 1, occupying anoverall space approximately two inches by two and one-quarter inches,and two and three-quarter inches high.

Figs. 1-3 show the construction of the individual relays. The twooperating coils of the front relay are indicated at .19 and 2G, and thereset coil at 21, this being the middle coil. The corresponding coilsand other parts of the relays on the back of the panel are indicated byreference numerals with the subscript a, and no further description willbe given. The three coils are alike, that is, they contain the samenumber of turns of the same gage wire and they are mounted in parallelrelation on vertical cores Z2, 23 and 24 which are connected together atthe top by means of a yoke member 25. The lower ends of the cores are ofa T-shape as shown in Fig. 1, these T-shaped ends forming pole pieces26, 27 and 28 which are spaced from one another to leave two air gapsbetween neighboring pole pieces.

The movable part of each relay consists of a swncn member or rocker,these rockers being designated as 29 and 39, respectively. Each rockeris of insulating material such as plastic and has a hub portion 31 witha tubular downward extension 32, and a slender upper portion 33terminating in a T-shaped head 34. Hub portion 31 has a trunnion mountedon a suitable bearing stud 35 which may be press-fitted into an aperturein the lower end of an extension 36 of yoke member between the coils.The rockers are retained on studs in any suitable manner as by means ofsnap rings 37.

A small elongated cylindrical permanent magnet 38 is mounted within thetubular extension 32 of each of the switch members or rockers 29 and 30and the lower ends of these permanent magnets extend into operativerelation with their associated pole pieces at the lower ends of the coremembers 22, 23 and 24. Thus the lower end of permanent magnet 38 ofrocker 29 extends into the air gap between the ends of the T-shaped polepieces 26 and 28 whereas the permanent magnet 38 of rocker 30 extendsinto the air gap between the pole pieces 27 and 28.

The fixed contact members of the relays are shown at 39, 4t) and 41,these preferably comprising geometrically similar stampings each havinga base portion 42 which fits against the flat face of panel 4 from whicha horizontal flange 43 is bent outwardly from the lower edge. Theopposite ends of this flange are bent upwardly at an angle of about 45and the outside horizontal edges or corner portions 44 of such portionsconstitute the portions of the fixed contacts which are engaged by themovable contact members of the relay.

The fixed contact members 39, 4'0 and 41 are assembled in pairs onopposite sides of the panel 4 in engagement with the respective contactmounts 16, 11 and 12 on the front and 10a, 11a and 12a on the rear. Theyare then attached to the panel by means of hollow rivets or eyelets 45.To facilitate assembly the contact members are preferably provided withpairs of lugs 46 which rest upon the top edge of the panel.

The movable contact members of each switch member 29 and 30 arepreferably formed of so-called brush wire. The wire is fairly stiff,quite resilient and highly conductive. Each movable contact member ispreferably made of a number of separate wires but for simplicity onlyone is shown on each side of the rocker in the sample selected forillustration. These two wires are indicated at 47 and 48. Except attheir lower ends these wires are normally straight, but are held inslightly bent position when mounted on the switch members.

At their lower ends they are bent to form in effect fiat hooks 49whereby the wires may be fixedly supported in an aperture in a fixedmetal flange or step 50 projecting from the short outer leg of a metalclip 51 which is U- shaped in plan view but has an inner leg 52 which islonger than its outer leg. This clip is attached by means of a hollowrivet 53 to mount 14 on the face of panel 4. The contact wires 47 and 48for switch member 30 are similarly fixed at their lower ends in asimilar U-shaped clip 54 which is attached to mount 15 by means ofhollow rivet 55. It will be understood that the construction is similaron the rear side of the panel, the U-shaped members there beingdesignated by the subscript a and attached against the respective mounts14a and 15a (Fig. 7).

Wires 47 and 48 extend upwardly from their supporting aperture in themetal step 50 and are sprung outwardly and received in grooves in thebulging hub 31 of the switch member. Their upper end portions projectthrough apertures 56 in the T-shaped head 34, being held in position eapertures and by the hub grooves. Wires 47 and 48 extend a sufficientdistance above the head 34 to engage the fixed contact members 39, 40 or41 when the switch members are rocked in one direction or the other andcomplete an electric circuit therewith. Apertures 56 are preferablyslightly larger than the wires 47 and 48 so as to allow the wires toride loosely therein. The construction provides a slight wiping contactof the wires with the fixed contact members which is suflicient to keepthe contacts clean without undue wear.

For illustrative purposes the switch members 29 and 3G in Fig. 1 havebeen shown in mid position, but it will be understood that in actualoperation the permanent ma nets 38 will always be in contact with one oftheir adjacent pole pieces so that the contact wires 47 and 43 will beswung either to the left or right and one of these wires will engage itsadjacent fixed contact member. In other words the switches are of thesingle pole two-way type.

The operation of the double relay shown in Fig. 1 will now be referredto and in this discussion it will be assumed that the lower end of eachof the two permanent magnets 38 has north magnetic polarity, and it willbe further assumed that the north pole of the magnet for each of theswitch members 29 and 30 is in contact, respectively, with the polepiece 26 of the core of the left hand coil 19, and the pole piece 27 ofthe core of the right hand coil 29. Thus switch member 29 has beenrocked to electrically connect the clip 51 with the central stationarycontact 41 through its wire 48, and switch member 30 has been rotated toconnect clip 54 with central stationary contact 41 through its Wire 47.

Assume now that operating coil 19 is energized in a direction to producea north magnetic pole in its pole piece 26. There is a path for thesouth magnetic flux extending from the upper end of this coil throughyoke 25 and center core 24 to pole piece 28, thus forming a south polein this pole piece. The resultant interaction of the electromagnetic andpermanent magnet fields will be to cause the permanent magnet of switch29 to shift from pole piece 26 of the left-hand core into engagementwith pole piece 28 of the center core. This moves the upper end ofswitch member 29 to the left thereby disconnecting wire 48 from thecentral stationary contact 41 and engaging wire 47 with the left-handfixed contact 39. Accordingly, the connection of clip 51 is shifted fromcontact 41 to contact 39.

This Will not affect the position of switch member 30 Whose permanentmagnet 38 remains in engagement with pole piece 27 of the right-handoperating coil However, should it be desired to actuate switch member 30the energization of operating coil 2% in a direction to cause pole piece27 to have north magnetic polarity will result in the permanent magnetof switch member 3ft moving to the left into engagement with the centerpole piece 23. Thereby the connection of clip 54 is shifted from centralstationary contact 41 through wire to the right-hand stationary contact46 which is now engaged by wire 48. I

Only a momentary or instantaneous energization of coils 19 and 20 isrequired to produce the shifting of the switch members 29 and 30 asdescribed, inasmuch as they will be held in the positions to which theyhave been shifted by the magnetic attraction of their respectivepermanent magnets 38. These magnets each remain in engagement with polepiece 2% after the current has been cut ofi through operating coils 19and 20 because of the south magnetic poles which will be induced in thepole piece 28 by each of the permanent magnets 38 through the closedmagnetic paths from the upper ends of magnets 38, which paths arecomprised by the studs 35, the yoke extensions 36, the yoke and thecenter core 24.

Now, if it should be desired to throw switches 29 and 311 in theopposite direction, that is, back to their original positions, this canbe done simultaneously by energizing the center or reset coil 21 in thedirection to cause pole piece 28 to have north magnetic polarity. Theflux issuing from the top of coil 21 has a divided path to the left andright through yoke 25 in both directions, and then downwardly throughcores 22 and 23 to the respective pole pieces 26 and 27, therebyproducing south magnetic poles in both of these pole pieces (coils 19and 21 not being energized). Hence a repulsion is produced between thenorth pole of each of the permanent magnets 38 of the respectiveswitches 29 and 30, and the pole faces of pole piece 28, andsimultaneously an attraction is produced between such permanent magnetsand the adjacent south poles. In the case of switch 29 this is polepiece 26, and in the case of switch 39 it is pole piece 27.

The two switches will be held in their respective positions justdescribed by means of their permanent magnets. Only an instantaneousenergization of reset coil 21 is required. In the reset position ofswitch 29, clip 51 will be disconnected from stationary contact 39, wire47 moving out of engagement therewith, and a connection will beestablished to stationary contact 41 through wire 68. Similarly, switchwill be disconnected from stationary contact 40, wire 43 of this switchleaving contact therewith, and will be connected with stationary contact4-1, since wire 47 will engage this contact.

The switch members 29 and 30 will be held or locked, by the action oftheir respective permanent magnets 38, in the positions to which theyare actuated, regardless of the direction of actuation.

Neither permanent magnet will be de-magnetized because when any of thethree operating coils 1%, 20 or 21 is energized, there is always amagnetic flux path of low reluctance in parallel with the flux path ofthe respective permanent magnets 38 so that the flux produced by thecoil which is energized will follow such path of low reluctance insteadof endeavoring to de-magnetize the permanent magnet. For example, whenthe reset coil 21 is energized in such a way as to produce a north polein pole piece 28, the flux issuing from the top of center core 24. hasreturn paths through yoke member 25 and the outer cores 22 and 23 to thepole pieces 26 and 27, with only a relatively small air gap betweenthese pole pieces and the lower ends of the permanent magnets 36;consequently any de-magnetizing effect on these permanent magnets byflux attempting to pass through the yoke extensions 36 is small andineffective.

It will be understood that the connections between the various operatingcoils 19, 20 and 21 on one side of the panel 4, and 19a, 20a and 21a onthe opposite side may be made to the contact strips S1S12 as requiredfor the intended use of the relays. This also applies to the connectionsbetween clips 51 and 54 and 51a and 54a (which connect to the movableswitch contact members) and the stationary contact members 39, 4t andl1, and 3%, 411a and 41a. As shown in the drawings, clip 51 is connectedto contact strip S3 through the clip mount 14 and a contact extension.Similarly, clip 54- is connected through its mount 15 to contact stripS6. Likewise, on the opposite side of the panel, clips 51a and 54a areconnected with contact strips S9 and S12 through the respective mounts14a and 15a and contact strip extensions.

Also, as shownin the drawings, one terminal of each of the six operatingcoils 19, 20 and 21, and 19a, 20a and 21a is connected to a commoncontact strip S10 on the back of the panel. As mentioned previously, theconductors used for this purpose (not shown) consist preferably ofordinary flexible insulated wires, and the three wires leading from rearcoils 19a, 20a and 21a are to be soldered to the upper end of contactstrip S10. The conductors leading from front coils 19, 20 and 21 are tobe soldered to a member 57 on the front side of the panel which issecured in place by means of two eyelets, one of which, makes electricalconnection with the upper end of rear contact S10. In this way one leadof each of the six coils is commoned on the single contact strip S10.

It will be understood that the opposite leads of the six coils areconnected to other of the contact strips. For example, the oppositeterminal of coil 19 is connected through a wire conductor (not shown) tothe upper end of contact strip S1, while the corresponding lead fromcoil 21? is connected to contact strip S5. in like manner the freeterminal of reset coil 21 is connected to contact strip S4. The oppositeterminal of rear reset coil 21a is also connected to contact S4 (througheyelet 59) so that in the relay illustrated the switch members on bothsides of the panel are reset simultaneously. The opposite erminals ofthe other two rear coils 19a and 26a may be connected to the remainingfree contact strips 37 and S11, respectively.

In this manner the external operating circuits may be connected with theoperating coils of the relay, and the external circuits which are to bemade and broken by the four two-way switches 29, 30 and 29a, 30a may beconnected with the contacts of these four switch members. It will beunderstood that the external connections to the operating coils and theswitches of the relay may be made in other ways, but the mounting of therelays in pairs on the front and rear of panels such as panel 4, andhaving the contact strips at the bottom which make contact with theexternal circuits through the fingers F1- F12 on the base 1 as shown inFigs. 4 and 5, afford a means for mounting the relays in an extremelycompact form.

. Furthermore, the mounting of the relays on such supporting panelsprovides a construction which lends itself well to manufacture of therelays in large quantities and at minimum cost, and the assembling ofthe parts by means of rivets, preferably of the eyelet type to reduceweight and use of metal, eliminates all screw threaded connections, orconnections of any other type which are likely to be loosened byvibration.

A particular example of the present construction which possesses suchadvantages is illustrated in the manner of attachment of the relays topanel 4. The panel is provided with a series of keyhole-shaped apertures60. Each of these has an enlarged circular upper portion and a narrowerslotted lower portion and the apertures are positioned in the panel atapproximately the bottom of the two relay structures.

in assembling the relays on panel 4 a rodlike support 61 (Fig. 3) isslipped into each of the three apertures 60. These rodlike supports 61are screw-machine-made parts made from a section of metallic rod such asbrass having a diameter which may easily be inserted in the uppercircular portions of apertures 60. Such supports are grooved centrallyas indicated by numeral 62 and again near each end as shown at 63 and64. In placing a support 61 in one of the apertures the central groovedportion 62 is received in the lower slotted portion of the aperture, thewidth of the groove 62 fitting the thickness of the panel.

After a support 61 has been placed in each of the three keyhole-shapedapertures 60, a pair of relays is presented to the panel. These relayswill have been previously assembled by placing the coils on therespective cores 22, 23 and 24, the pole pieces 26, 27 and 28 beingformed integrally with the lower ends of the cores, and thenriveting'the upper ends of the cores to the cross yoke member 25 at thethree places indicated in Fig. l, The studs with the two switch members2? and 30 can be mounted in position on the lower ends of the yokeextensions 36, either before or after the yoke is attached.

With the reiays thus assembled a slot 65, which extends upwardly aslight distance from the central lower edge of each of the pole pieces26, 27 and 23, is fitted into the groove 63 of each of the supports 62on the front side of the panel, and the relay on the rear side of thepanel is similarly rested in the slots 65 at the rear ends of thesupports 61. Thereupon the yoke members 25 and 25a of the two relays areheld against the opposite faces of the panel and two eyelets 65 areapplied through two apertures 56 previously formed in panel 4.

in the foregoing specification I have described in detail the preferredform of my improved relay as designed for quantity production but it isto be understood that the structure disclosed may be variously modifiedwithout loss of advantage. For example, the movable contacts could be atthe lower ends of the strips 47, 48 with c0- operating contact facesformed on the parts, 26, 27 and 23.

it will also be understood that such variations in the arrangement andconstruction of the parts of the relay structure may be made withoutdeparting from the scope of the invention as set forth in the appendedclaims.

I claim:

1. An electromagnetic latch relay comprising an operating coil and areset coil having parallel cores connected at one end by a yoke, saidcores having pole faces at their opposite ends forming an air gap, apivotally mounted armature having a hub portion with a permanent magnetattached on one side of said hub and a contact supporting portion on theopposite side of said hub and approximately in line with the axis ofsaid permanent magnet, said magnet having one end disposed in said airgap, stationary contact members positioned adjacent the opposite end ofsaid armature at the sides thereof, a fixed support adjacent the freeend of said permanent magnet, a pair of resilient wires forming themovable contact members of the relay, said wires being mounted on and insubstantially parallel relation to said armature and being attached atone end to said fixed support, the opposite end portions of'said wiresbeing attached to said armature contact supporting portion and beingmovable thereby into and out of engagement with said stationary contactmembers.

2. An electromagnetic latch relay comprising an operating coil and areset coil having parallel cores connected at one end by a yoke, saidcores having pole faces at their opposite ends forming an air gap, apivotally mounted armature of insulating material having a hub portionwith a permanent magnet attached on one side of said hub and a movablecontact supporting portion on the opposite side, said permanent magnethaving one end disposed in said air gap, a pair of resilient wiresdisposed on opposite sides of said armature and projecting beyond bothends thereof, a stationary support substantially in axial alignment withsaid armature, said support having said wires fixed thereto at one end,and stationary contac members positioned to be engaged by the sides ofthe opposite projecting portion of. said wires respectively, said wiresfrictionally engaging the hub portion and the ovable contact supportingportion of the armature and bein held in operative position by their ownresilience.

an electromagnetic latch relay comprising an operatand a reset coilhaving parallel cores connected c end by a yoke, said cores having polefaces at osite ends forming an air gap, 21 nivotailv mounted armature ofinsulating material having a hub portion with a permanent magnetattached on one side of said hub and a movable contact supportingportion on the opposite side thereof terminating in a T.-shaped head,

said permanent magnet having one end disposed in said air gap, a pair ofresilient wires disposed on opposite sides of said armature and formingthe movable contact members of the relay, a contact support mounted instationary position centrally with respect to said pole faces, saidwires being attached at one end to said support and having theiropposite end portions projecting through apertures in said T-shapedhead, the central portion of said wires being sprung outwardly andfrictionally engaging the opposite sides of said hub to-hold the wiresin position on the armature, and stationary contact members positionedto be engaged by the sides of said respective wires.

4. An electromagnetic latch relay comprising three coils having parallelcores connected at one end by a yok the cores having pole faces at theiropposite ends forming two air gaps, said yoke having extensions directedtowards said air gaps and terminating intermediate the ends of saidcoils, armatures pivoted at the ends of said extensions for rockingmovement parallel with the surfaces of the extensions, each armaturecarrying a permanent magnet projecting beyond the extension and into thecorresponding air gap, movable contact means carried by each of saidarmatures, and stationary contact means cooperating therewith, themomentary energizing of either of said outer coils causing its adjacentarmature to move into engagement with one of its adjacent pole facesthereby closing the armature contact means against one of itscooperating stationary contacts, and the momentary energizing of themiddle coil causing said armature to engage its opposite adjacent poleface and the other armature to hold a symmetrical position therewith,the permanent magnet of each armature having a substantially continuousmagnetic flux path through its associated yoke extension to said yokeand therethrough to the cores of said coils, the flux from saidpermanent magnets producing magnetic poles in the pole faces of saidcores which are of opposite polarity to the permanent magnet poleswithin the air gaps thereby holding said permanent magnets in engagementwith the pole faces against which they have een moved by the energizingof any of said coils and thereby latching the armatures in suchcorresponding positions until such time as a coil is reenergized.

5. An electromagnetic relay comprising an operating coil and a resetcoil having parallel cores connected at one end by a yoke, said coreshaving pole faces at their opposite ends forming an air gap, a pivotallymounted armature having a hub with a permanent magnet portion on oneside of said hub and a contact supporting portion on the opposite sideof said hub, said permanent magnet having one end disposed in said airgap, stationary contact members positioned adjacent the opposite end ofsaid armature, and movable contacts carried by said contactsupportingportion and cooperating with said stationary contact members.

6. An electromagnetic relay comprising two operating coils havingparallel cores connected at one end by a yoke, a rocker armature, meansfor pivoting said armature for rocking movement between said cores, saidarmature having a permanent magnet mounted thereon between said pivotand one end of the armature, movable contact members comprising a pairof spring metal wires attached to said armature and extending paralleltherewith on opposite sides thereof and projecting beyond one end ofsaid armature, means for anchoring in fixed position the ends of saidwires which project beyond the end of said armature so as to maintainthe armature normally in mid-position between the two cores, andstationary contact members arranged to cooperate with said wires,

. one of said members being engaged by the side of one of said wireswhen the armature is rocked in either direction.

7. A polarized relay comprising two coils having cores terminating inspaced poles, a middle coil arranged bet tween said two coils, saidmiddle coil having a core disposed centrally between the cores of thetwo outer coils and forming with the poles of said cores two pairs ofspaced poles, two rocker armatures arranged on opposite sides of saidmiddle coil with the outer ends of their permanent magnets disposedbetween said respective pairs of poles so that the two rocker armaturesmay be simultaneously operated by energizing the middle coil andseparately operated by energizing the respective outer coils.

References Cited in the file of this patent UNITED STATES PATENTS 10Nicholson Jan. 12, 1909 Chippen May 29, 1917 Leighton Mar. 22, 1927Atherton Aug. 19, 1930 Lum Mar. 24, 1936 Koenig Aug. 3, 1948 Merkel Dec.28, 1948 FOREIGN PATENTS Sweden Apr. 10, 1945 Great Britain Oct. 18,1945 Germany Jan. 5, 1943

